Living systems, particularly higher animals, such as mammals, comprise many complex networks of interacting genes and gene products. In order to understand the functions of such networks in both health and disease, several large-scale analytical technologies have been developed for making genome-wide measurements, including measurements of genetic variation, gene expression, gene copy number variation, and like phenomena, e.g. Lochhart et al, Nature Biotechnology, 14: 1675-1680 (1996); DeRisi et al, Science, 278: 680-686 (1997); Golub et al, Science, 286: 531-537 (1999); Kennedy et al (2003), Nature Biotechnology, 21: 1233-1237; Gunderson et al (2005), Nature Genetics, 37: 549-554; Pinkel and Albertson (2005), Nature Genetics Supplement, 37: S11-S17; Cobb et al, Proc. Natl. Acad. Sci., 102: 4801-4806 (2005). Such technologies commonly provide highly parallel readouts by the use of large arrays of hybridization probes whose positions are known or determinable; thus, signals at each particular probe site can be related to a genetic measurement, and the collection of array signals can be related to genome-wide response or state. Miniaturization has proved to be extremely important for increasing the scale and reducing the costs of such approaches. However, further increases in scale and reductions in cost would be highly desirable, particularly for measurements of genetic phenomena in complex organisms, such as humans.
In view of the above, it would be advantageous for the medical, life science, and other applied biological fields if there were available molecular arrays and arraying techniques that permitted efficient and convenient analysis of large numbers of target molecules, such as substantially all expressed genes in a mammalian-sized genome, in parallel in a single analytical operation.